Bismuth(III) triflate was found to promote the formation of stable cyclic N-acyliminium species in remarkable catalytic amounts (1 mol %). The alpha-amidoalkylation process seems to be effective in intermolecular and intramolecular manners leading to alpha-substituted lactams and heterocyclic systems containing azacycles, respectively. By comparing our results with those obtained with the classical Lewis acids as catalysts, it was evidenced clearly that the use of bismuth(III) triflate had been efficient for nearly all alpha-acetoxy lactams we used, except for N-acyliminium precursors bearing a sulfur atom. Also, the process seems to be easy, general, and clean, having diastereoselectivity comparable to protocols using classical Lewis acids and resulting in the formation of polyheterocyclic systems in good to excellent yields (64-99% in acetonitrile as solvent).

The antimicrobial activity of 3-methyl-5-isopropyl (or ethyl) 6-methyl-4-nitrophenyl-1,4-dihydropyridine-3,5-dicarboxylate derivatives was evaluated. Prokaryotes (bacteria) appeared to be more sensitive to their antimicrobial activity than were eukaryotes (filamentous fungi). The best antibacterial activity was shown by derivative 33, which was able to inhibit the growth of Mycobacterium smegmatis (MIC33 = 9 μg.ml−1), Staphylococcus aureus (MIC33 = 25 μg.ml−1), and Escherichia coli (MIC33 = 100 μg.ml−1). In addition, derivative 4 demonstrated its antibacterial power on the acid-fast bacterial species M. smegmatis and on Gram-positive S. aureus. Focusing on the structure-activity relationship, it appears that the increase in the substituent bulk at the C2 position improved the antibacterial activity of the set of compounds studied. Derivatives 33 and 4, carrying 2-cyano-3-oxo-3-phenylprop-1-en-1-yl and allyliminomethyl groups, respectively, showed significantly higher inhibition activities on all tested microorganisms in comparison with the rest of the derivatives. This enhancement was also in good correlation with different log P values (lipophilicity parameter).

For Abstract see ChemInform Abstract in Full Text.

A convenient route to thienoquinolizidinones is described starting from ethyl pipecolinate and suitable halogenomethylthiophenes or 3‐chloromethylbenzothiophene. The Schmidt reaction and the Beckmann rearrangement of oximes of these ketones led to piperidino[1,2‐a][1,3] or [1,4]diarepines fused to a thiophene ring.

Benzo(or furo)[5,6]azepino[2,1-a]isoindolone and derivatives were obtained easily in one-pot via N-acyliminium ions by treatment of 2-(2-methoxycarbonylbenzyl(or fur-3-yl))phthalimide with alkylmagnesium iodide followed by an acidic hydrolysis.

Dihydrofuro[2,3-f]indolizidinone obtained from biosourced reagents even at multigram-scale, was used as advanced building-block with up to five points of chemical diversification. This resulted in the sequential synthesis of a series...

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(R)- and (S)-alpha-phenylethylamine (alpha-PEA: 7) have been used separately to resolve successfully a racemate 2-formyl-1,4-DHP derivative 4. The process was based on the difference of the solubility of both Schiff bases (6) since one of them crystallized out from the solution. These imines obtained by condensation of (R)-alpha-PEA (7) or (S)-alpha-PEA (7) with aldehyde (rac-4) were separated and analyzed by X-ray diffraction, and their exposition to an hydrochloric hydrolysis conditions led to the enantiopure (4R)-4 or (4S)-4 in excellent yields. Separate condensation of other chiral (8 and 13) and racemic (18) amino thiols as auxiliary with rac-4, (4S)-4, or (4R)-4 is accompanied by an in situ crystallization-induced dynamic resolution, whereby one distereomer of thiazole template selectively precipitates and can be isolated by simple filtration in 76-82% yield with dr > 99. The thiazole species isolated from this process resulted from an amino aldehyde condensation followed by a spontaneous thiol-imine cycloaddition. Finally, the racemate (+/-)-(4R,2'R)-19 and the diastereomerically pure homologous (4S,2'R)-23 and (4R,2'S)-20 (obtained in good yields (79-82%) from 2-aminoethanethiol (18) and 2-formyl-1,4-DHP derivative rac-4, (4S)-4, or (4R)-4, respectively) were converted conveniently in a one-pot procedure into newly tricyclic thiolactams in the DHP series in racemic ((+/-)-(6R,9bR)-21, 72% yield)) and enantiopure ((6S,9bR)-24, 71% yield); (6R,9bS)-24, 70% yield) forms.